Integrated circuits fabricated using modem deep submicron processes operate at relatively low supply voltages, but may be required to inter-operate with legacy devices that operate at relatively higher voltages. Unfortunately, the higher voltages of such legacy devices present serious reliability problems for the thin-oxide field-effect transistors (FETs) made available by advanced processes and preferred for high-speed communication. Circuits that support communication at higher voltages in support of legacy devices therefore employ high-voltage-tolerant devices, such as thick-oxide transistors, in place of higher performance devices.